Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.11.1.7 (peroxidase)
 65,474 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Soybean lipoxygenase shows a secondary peroxidase/oxidase activity: The aerobic reaction with isobutanal, enhanced by hydrogen peroxide as a cosubstrate, yields acetone, exhibits chemiluminescence and consumes oxygen (phi cl = 1.3 x 10(-9) photons/O2 molecule consumed). 9,10-Dibromoanthracene-2-sulfonate increases the photoemission (kET tau 0 = 2 x 10(4) M-1; phi cl = 0.9 x 10(-7) photons/O2), whereas it is diminished by sorbate, tryptophan, 2-methyl-1,4-naphthoquinone, glutathione, and superoxide dismutase. In the presence of hydrogen peroxide the lipoxygenase reaction with glutathione yields yet another excited state. From the well-known reactions promoted by horseradish-peroxidase, these features are concluded to indicate the novel activity of soybean lipoxygenase. With isobutanal as a substrate lipoxygenase acts as an oxidase and as a peroxidase. The mechanism suggested leads to photoemissive triplet excited acetone as expected from the cleavage of an intermediate dioxetane.
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PMID:The peroxidase/oxidase activity of soybean lipoxygenase--I. Triplet excited carbonyls from the reaction with isobutanal and the effect of glutathione. 250 78

Hemin can substitute for horseradish peroxidase as a catalyst for the aerobic oxidation of isobutanal to acetone and formate. Previous studies have shown that the chemiphosphorescent emission observed in the enzyme-catalyzed reaction is due to the production of acetone in its triplet state. Although no chemiphosphorescence is observed with the model system (hemin), generation of triplet acetone in this system is indicated by an analysis of data for energy transfer to the 9,10-dibromoanthracene-2-sulfonate ion and for interception of the excited species by the sorbate ion, a known triplet quencher. These data are compared to those obtained with triplet acetone generated by thermal cleavage of tetramethyldioxetane in aqueous solution. The results are in agreement with the hypothesis that the quenching of triplet acetone by oxygen is less efficient in the enzyme catalyzed reaction, pointing to a protective role for the apoenzyme in that system.
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PMID:Hemin-catalyzed generation of triplet acetone. 739 46

The hydrolysis of 2-methyl-1-propenylbenzoate catalyzed by esterase produces 2-methyl-1-propenol, which can be subsequently oxidized by the H2O2/horseradish peroxidase (HRP) system to yield electronically excited triplet acetone. The level of luminescence elicited by this species is proportional to total esterase used, making it possible to determine as little as 2 pmol of esterase. Yet, its intensity can be enhanced several orders of magnitude by fluorescent acceptors like sodium 9,10-dibromoanthracene-2-sulfonate. The system works as a chemiluminescent reaction triggered by esterase and can be used to elaborate analytical assays to determine its activity. This chemiluminescence is also promoted by HRP conjugates instead of free HRP and, hence, this simple reaction system can also be used to develop sensitive chemiluminescent immunoassays based upon peroxidase activity.
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PMID:Esterase coupled with the H2O2/horseradish peroxidase system triggers chemiluminescence from 2-methyl-1-propenylbenzoate: a potential analytical tool for esterase analysis. 871 1

Esterase from monocytes promotes the hydrolysis of 2-methyl-1-propenylbenzoate (MPB) yielding 2-methyl-1-propenol, which is oxidized by horseradish peroxidase/H2O2 producing triplet acetone. The chemiluminescence of this reaction can be enhanced by the addition of 9,10-dibromoanthracene-2-sulphonate. The non-specific esterase present in monocytes is responsible for MPB hydrolysis, since (a) the chemiluminescence of the reaction was inhibited by fluoride, and (b) cells that do not contain a significant amount of non-specific esterases, e.g. lymphocytes and neutrophils, did not trigger light emission. The analytical application of this reaction is considered.
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PMID:Chemiluminescent determination of esterases in monocytes. 974 43